Means for burning liquid fuel in furnaces for heating buildings



Jan. 14, 1930. A. B. FRENIER 1,743,205

MEANS FOR BURNING LIQUID FUEL IN FURNACES FOR HEATING BUILDINGS Original Filed Aug. 6, 1925 Patented Jan. 14, 1930 UNITED STATES PATENT OFFICE I ALBERT B. FBENIER, OF CHICAGO, ILLINOIS, ASSIGINI'OR, BY MESNE ASSIGNKIENTS, TO PETROLEUM HEAT AND POWER COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE MEANS FOR BURNING LIQUID runnm summons ronnnarine BUILDINGS Original applicationmedhugust 6, 1925, Serial No. 48,464. Divided and this application filed November 8, 1926. Serial No. 146,950.

This invention relates to improvements in liquid fuel burning apparatus more especially adapted for use with steam or hot water boilers or hot air furnaces for heating homes or other buildings, and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

In the burning of liquid fuel, especially non-volatile or heavy hydrocarbons, the fuel is either atomized wholly or in part or is vaporized, and isthen mixed with air and with the air is forcibly discharged into an open combustion chamber, wherein it is igtically confined therein until combustion is' practically complete. Such method and combustion chamber are described in Letters- Patent No. 1,284,182 to Doble,-November 5,

' 1918, and in a patent granted to the present inventor, No. 1,379,008, May 24, 1921.

In an application for patent hereinbefore filed by me on the 6th day of August, 1925, Serial No. 48,464, I described a method for burning liquid fuel in furnaces, whereby the inert products of combustion are introduced with the air included in the combustible mixture of oil and air supplied to the burner in order to slow down or retard combustion in the confines of the combustion chamber, thereby softening the flame and reducing the noise attendant upon the burning of the fuel in such a combustion chamber.

In carrying out said method combustion supporting air alone is initially introduced with the fuel into the combustion chamber, the mixture is ignited and is thereafter burned within the combustion chamber; when combustion is practically complete and a maximum temperature of combustion has been obtained, there is thereafter injected with the air and in a predetermined ratio the point above the combustion chamber. The proportion of products of combustion is such as to delay combustion and reduce the noise thereof without expanding the flame materially beyond the vicinity of the combustion chamber. The combustible mixture including the products of combustion continues to burn in this manner until by reason of a thermostatic control associated with the burner the supply of liquid fuel is cut off whereupon the flame goes out and the burner is idle until a combustible mixture is again supplied to the combustionchamber and ignited, whereupon follows the same cycle as herein-above described. ,The object of the present invention is to provide a novel and efiicient device by means of which the introduction and supply of the products of combustion to the burner, in the manner intended by the process hereinbefore referred to, is brought about and controlled. The subject matter of this application is one of the devices presented in the aforesaid application, Serial No. 48,464, of which the present application is a division- The advantages of the invention will appear more clearly as I proceed with my specification.

In the drawings- Figure 1 represents a side elevation of a familiar domestic furnace, with a liquid fuel combustion chamber mounted within the fire-box and a liquid fuel atomizer automatically controlled for spraying liquid fuel mixed. with air into said combustion chamber, such as described in my aforesaid patcut, the same being provided with ,an apparatus for introducing the products of combustion with the air in accordance with my invention.

Figure 2 is. a detail View on an enlarged scale partly in elevation and partly in section, illustrating a pneumatically operated device for controlling the introduction of the products of combustion with the air supply to the combustion chamber.

v Figure 3 is a view representinga transverse section through Figure 2 in a plane indicated by the line 33 of Figure 2.

Referring now to that embodiment of the invention illustrated in the drawings10 indicates a furnace of any usual construction provided with a fire-box 11 and with a stack 12 through which the products of combustion are discharged. 13 indicates a combustion chamber, which in this case, is a heavy metal box-like structure adapted to confine the flame. 14 indicates an electric motor driven fan or blower, bymeans of which fresh air is normally discharged. through a pipe 15 into the combustion chamber, said air acting in the example illustrated to atomize the liquid hydrocar on fuel supplied by a pipe 16 from any convenient, suitably controlled source of supply prior to or as it is introduced into the combustion chamber 13. 43 indicates an electric motor, controlled by a thermostat or other or auxiliary automatic control, adapted to close and open the switch in the circuit of the fan motor and to actuate the ignition device, as by opening and closing the valve supplying a pilot flame in the combustion chamber. Said parts of the apparatus are familiar and may be as tile 5*" scribed in the patent referred to and require no further illustration or description.

17 indicates a pipe or conduit of comparatively small cross-section which is adapted to introduce the inert gas, in this case a part -of the products of combustion, along with .the air into the fan casing, whence it is discharged with the fresh air through the pipe 15. The conduit 17, as illustrated, is connected in any suitable manner, as by a fitting 18 to the stack 12. The other end of said conduit is attached to a nipple 19 providing an inlet port to a valve casing 20 which opens by a passageway 21 into the casing of the fan or blower 14. Belong the inlet nipple 19 on the diametricallyopposite side of the valve casing 20 is an inlet port 22, for the admission of fresh air. An-ordinary butterfly valve 23 is mounted in the valve casing 20 on a s indle or shaft 24 which projects at one en beyond the valve casing 20.

, The butterfly valve 23, when in the position shown in full lines in Figure 3, cuts off the inlet opening for the products of combustion from communication with the passageway 21 into the casing 14 of the fan, and leaves said passageway full open to the inlet 22 for the entrance 0 air. With the valve in this position, the operation of the fan will draw into and discharge throu h the pipe 15, fresh air only. When said valve 23 is shifted clock-wise into the position shown in dotted lines at 23, the opening into the passageway 21, will be cut down or shut off on the side of the air inlet 22 and will be correspondingly opened on the side of the prodnets of combustion inlet 19. Thus, in this position a certain definite proportion of the fluid discharged through the pipe 15 Will-be roducts of combustion and the balance will saw; and the proportion of the products of combustion to the air of the mixture will depend upon how far the valve 23 has been shifted clock-wise. Thus, by this means a positive control of the proportions of the products of combustion or inert gas, as compared to the air, is provided.

'may be limited in any convenient way, As shown in Figure 3, a bolt 23 fixed in "the eylindrical wall of the valve casing 20 is placed in the path of an end of the valve 23 at a point so that the valve will strike the bolt when the intended limit of movement of the The rotative movement of the valve 23 valve is reached. The bolt is engaged in a slot 23 in the valve casing wall with its head on the inside of the valve casing and a nut 23 engaged against the outside periphery of saidcasing. By this construction the position of the stop bolt may be varied to adjust the limit of opening movement of the valve and the resultant proportion of inert gas introduced with the air.

A diaphragm chamber 33 is connected with )the air supply pipe 15 atsome point intermediate the fan casing 14 and the burner 13. The diaphragm casing may be of any usual one side by an apertured rod 34 with. the air pipe 15. The rod 34 has a small bore 35 and has threaded laterally into it, a set screw 36, by means of which the effective cross-sectional area of said bore may be determined. 37 indicates the diaphragm in the casing. Said diaphragm is exposed on its side nearest the pipe 15 to the air pressure in the pipe 15 by reason of the connection of the diaphragm casing on that side of the diaphragm with the pipe 15 through the bore of the pipe 34.

The diaphragm on its upper side has fixed to it a pin 38, which'has suitable bearin for vertical movement in the upper side 0 the diaphragm casing, beyond which it projects to be pivotedat- 39 to a lever 40. The lever 40 is fulcrumed to a stud 41 rising from the diaphragm casing on the side remote from the valve casing 20 and the other end of said lever 40 is connected by a link 42 to the crank arm 31.

The operation of the pneumatic control is as follows When air is discharged by the fan through the pipe 15 to begin combustion in the combustion chamber 13, pressure is built up in the pipe 15 and this pressure or familiar construction and is connected on gradually builds up through the bore 35 of area of the bore 35 asdeterlnined by theset screw 36, this pressure will have been built up far enough to lift the diaphragm 37 and through the pin 38 to operate the lever 40, so as to swing the valve 23 from the position shown in full lines in'Figure 3 to the position shown in dotted lines 23 therein, as heretofore described. Thus, the products of combustion are introduced with the air supply after the lapse-of a predetermined time interval from the initial ignition of the gombustible mixture in the combustion cham- While in illustrating and describing the invention I have shown an apparatus which contemplates preferably a complete atom ization of the liquid fuel prior to or as it enters the combustion chamber, it will be understood that the invention is applicable, whether the fuel is completel atomized, atomized only in part or vaporized wholly or in part, either prior to its injection into the combustion chamber or at the instant it is injected into the combustion chamber or subsequent to its injection thereinto. The word fuel therefore as used in the claims is to be understood to cover and include liquid fuel when atomeffective cross sectional area of the bore in said tube, and means operatively connecting said diaphragm to said valve.

In testimony that I claim the foregoing as my invention, I afiix my signature this 28th day of October, 1926.

ALBERT B. FRENIER.

ized, wholly or in part or vaporized, wholly or in part.

Again, the invention is not limited to use with a combustion chamber made of metal such as herein described,=but contemplates a combustion chamber made of any material designed to produce substantially complete combustion of the fuel within the combustion chamber; and it also contemplates a combustion chamber of any suitable form or shape which may function as a flaming combustible confining meansfor the prompt production of high temperature conditions. Such a combustion chamber or confining means may be an integral part of the oil burner proper or i may be built into the fire-box of the ordinary heating boiler or furnace.

I claim as my invention 1. In a liquid fuel burning apparatus in combination with a combustion chamber,

means for introducing a flame combustible into said combustion chamber, including an air inlet anda normally closedsecond inlet, means for igniting said flame-combustible, a conduit for leading an inert gas to said second inlet, a valve for opening said second inlet, a pipe intermediate said valve and said burner, a diaphragm chamber, a diaphragmtherein, a tube having a restricted bore therein connecting said pipe with one side of said diaphragm chamber, and means operatively connecting said diaphragm to said valve.

2. In a liquid fuel burning apparatus, in combination with a combustion chamber, mean for introducing a flame combustible into said combustion chamber, including an air inlet and a normally closed second inlet, means for igniting said flame combustible, a. conduit for leading an inert gas to said secondinlet, a valve for opening said second inlet, a pipe intermediate said valve and said burner, a diaphragm chamber, a diaphragm therein, a tube having a restricted bore therein connecting said pipe with one side of said diaphragm chamber, means for adjusting the 

